the element CROD could only transmit axial force (if you set the torsional stiffness to 0).
If you need to model a tension only element You should use a non linear material with a very low stiffness in compression.
To model a chain I think you should use many CBEAM elements. Keep bending stiffness very low and give correct axial stiffness.
Use sol 106 and PARAM LGDISP 1 (large displacement on).
In this way you are able to evaluate the correct sag of your cable.
You could try (I've never done) to release the bending DOF of beams end (5&6). in this case You must give to element bending stiffness iwo eliminate singularity.